MOLECULAR FUNCTION OF THE NF2 TUMOR SUPPRESSOR, MERLIN
I Andrea, Associate Professor
Massachusetts General Hospitalcity: Boston country: United States (us)
Grant 5R01CA113733-07 from National Cancer Institute
Abstract: Cancer develops when cells evade the rules that normally limit their proliferation. Growth factor receptors on the cell surface provide a critical interface between the cell and its environment and are the first intrinsic level of control. Growth factors are often continuously available, necessitating exquisite control of the receptors themselves to ensure that cell division proceeds only when warranted, for example during development, wound healing or normal tissue turnover. The distribution and aggregation of receptors across the plasma membrane is exquisitely choreographed; this, in turn, controls their signaling output and surface abundance via regulated endocytosis. The interface between the membrane and the underlying cortical cytoskeleton plays an active and dynamic role in this choreography. The neurofibromatosis type 2 (NF2) tumor suppressor, Merlin, and closely related ERM proteins (Ezrin, Radixin and Moesin), localize to the membrane-cytoskeleton interface and are poised to organize the distribution of, and signaling by, membrane receptors. During the initial funding of this proposal, we discovered that Merlin coordinates the establishment of stable adherens junctions (AJs) between cells with the inhibition of Epidermal Growth Factor Receptor (EGFR) internalization and signaling specifically in contacting cells, suggesting a molecular explanation for how cells achieve the phenomenon of contact-dependent inhibition of proliferation. More recently we have found that, by controlling the membrane distribution of EGFR, Merlin regulates the endocytic pathway taken by EGFR, which, in turn, dictates whether EGFR endocytosis is blocked by cell contact, suggesting a two-step mechanism whereby Merlin controls EGFR. Finally, our most recent studies suggest that Merlin may also control the membrane distribution of ErbB3 via a similar mechanism. Thus Merlin is poised to be a central regulator of the ErbB family of growth factor receptors (EGFR/ErbB1, ErbB2, ErbB3 and ErbB4) that have been implicated in nearly all forms of human cancer. In this application to extend this successful avenue of investigation we propose a multifaceted approach to extending our understanding of the molecular function of Merlin in controlling membrane receptor distribution and signaling. Specifically we plan to delineate the molecular basis of how Merlin controls EGFR membrane distribution and endocytosis and how Merlin stabilizes AJs and blocks EGFR endocytosis upon cellcell contact. We also plan to determine whether Merlin controls the surface availability of ErbB3 via a similar mechanism. We will carry out molecular, cellular and in vivo studies to examine the molecular function of the Nf2 tumor suppressor, Merlin. Specifically, we will test the hypothesis that Merlin controls the membrane distribution of and signaling from EGFR in a contact- dependent manner. We will also determine whether Merlin controls the ErbB family member ErbB3 via a similar mechanism. These studies will advance our understanding of the molecular cause of NF2 and of the biology of ErbB receptors that have been widely implicated in human cancer
Keywords: Actins; Adherens Junction; base; Biology; Cell division; Cell membrane; Cell surface; Cells; Clathrin; Complex; Cultured Cells; Cytoskeleton; Development; Endocytosis; Ensure; Environment; Epidermal Growth Factor Receptor; ErbB4 gene; ERM protein; Exhibits; ezrin; Family; Family member; follow-up; Funding; Goals; Growth Factor; Growth Factor Receptors; Half-Life; Heterodimerization; Human; In Vitro; in vivo; Investigation; Ligands; Malignant Neoplasms; Mediating; Membrane; Mitogens; Modeling; moesin; Molecular; Neuregulins; Neurofibromatosis 2; Neurofibromin 2; Normal tissue morphology; novel; Output; Pathway interactions; Patients; Play; Polyubiquitination; prevent; public health relevance; Publishing; radixin protein; receptor; Receptor Aggregation; receptor internalization; Role; Schwann Cells; Signal Transduction; Sterols; Surface; Testing; trafficking; tumor; Tumor Suppressor Genes; Tumor Suppressor Proteins; Work; Wound Healing
Relevance: We will carry out molecular, cellular and in vivo studies to examine the molecular function of the Nf2 tumor suppressor, Merlin. Specifically, we will test the hypothesis that Merlin controls the membrane distribution of and signaling from EGFR in a contact- dependent manner. We will also determine whether Merlin controls the ErbB family member ErbB3 via a similar mechanism. These studies will advance our understanding of the molecular cause of NF2 and of the biology of ErbB receptors that have been widely implicated in human cancer
Project start date: 2005-08-01
Project end date: 2015-05-31
Budget start date: 1-JUN-2011
Budget end date: 31-MAY-2012
PFA/PA: PA-07-070
5R01CA113733-07 (2011): $331162
Sponsored Links Excellgen http://Excellgen.com
Grants awarded to I Andrea
FUNCTIONAL CHARACTERIZATION OF THROMBOSPONDIN-2 IN BONE EXTRACELLULAR MATRIX
I Andrea, Research Investigator
University Of Michigan At Ann Arborcity: Ann Arbor country: United States (us)
Grant 1K01AR057427-01A2 from National Institute Of Arthritis And Musculoskeletal And Skin Diseases
Abstract: The objective of the 5 year career development plan outlined in this KO1 application is to foster the development of the candidate, Dr. Alford into a productive, independent investigator in the field of osteoblast cellular and extracellular matrix biology. Under the guidance of her mentors, Drs Steven A Goldstein and Renny T Franceschi, and through regular interactions with expert consultants, Stephen J. Weiss and Kurt D. Hankenson, the candidate will carry out the proposed research as a member of the Orthopaedic Research Laboratories in the Department of Orthopaedic Surgery at the University of Michigan. In the 5 year research plan proposed here, we will utilize primary MSC harvested from TSP2-null mice and their littermates in a well established in vitro model of osteoblastogenesis to test the global hypothesis that matrix-bound TSP2 makes specific contributions to osteoblast lineage progression which are dependent on the differentiation state of the cell, as well as on the unique extracellular milieu associated with matrix assembly, maturation and mineralization. Specifically, in aim 1 we will address the working hypothesis that in the context of early osteoblast-differentiation events, TSP2 promotes the assembly of a type I collagen-rich osteoblast-derived extracellular matrix, and as a result, it indirectly promotes collagen-dependent signal transduction events that are critical for osteoblast differentiation. In specific aim 2, we will address the premise that, in the context of matrix mineralization, TSP2 makes an additional unique contribution to osteoblast maturation. Specifically, we hypothesize that TSP2 is proteolytically processed to release biologically relevant fragments that affect matrix mineralization. Together, the experiments outlined in this proposal will define differentiation-stage dependent contributions that TSP2 makes to osteoblast lineage progression and matrix mineralization. A full understanding of how biochemical and physiological context influence the function of ECM molecules, such as thrombospondin-2, in marrow stromal cell lineage progression and osteoblast differentiation are essential in the design of therapeutics aimed at manipulating the environment of osteoblast precursors in order to promote bone formation under conditions of skeletal injury, aging or disease
Keywords: Address; Adenovirus Vector; Adenoviruses; Affect; Aging; angiogenesis; Binding (Molecular Function); Biochemical; Biology; bone; Bone Matrix; career development; Cell Culture Techniques; Cell Lineage; Cell physiology; Cells; Collaborations; Collagen; Collagen Type I; Conditioned Culture Media; Cytoskeleton; Data; design; Development; Development Plans; Disease; Environment; Estrogens; Event; extracellular; Extracellular Matrix; Extracellular Matrix Proteins; Family member; Fostering; Fracture Healing; Future; Genetic Transcription; Harvest; Homeostasis; In Vitro; in vitro Model; Integrins; Knockout Mice; Label; Laboratory Research; Lead; Length; lipid biosynthesis; Marrow; Matrix Metalloproteinases; Measures; Mediating; member; Mentors; Metabolic; Michigan; mineralization; Mitogen-Activated Protein Kinases; Molecular; Molecular Weight; Monitor; Mutation; Natural History; Null Lymphocytes; Orthopedic Surgery procedures; Orthopedics; osteoblast differentiation; Osteoblasts; Osteocalcin; Osteogenesis; osteogenic; Phosphorylation; Physiologic pulse; Physiological; Process; Protein Isoforms; protein structure; Proteolysis; Publishing; repaired; Research; Research Personnel; research study; RNA Interference; Signal Transduction; Site; skeletal; Skeletal Development; skeletal injury; Staging; Stromal Cells; Testing; Therapeutic; thrombospondin 2; Translations; Universities; Work
Relevance: A full understanding of how biochemical and physiological context influence the function of ECM molecules, such as thrombospondin-2, in marrow stromal cell lineage progression and osteoblast differentiation are essential in the design of therapeutics aimed at manipulating the environment of osteoblast precursors in order to promote bone formation under conditions of skeletal injury, aging or disease
Project start date: 2011-08-18
Project end date: 2016-08-17
Budget start date: 18-AUG-2011
Budget end date: 17-AUG-2012
PFA/PA: PA-10-056
1K01AR057427-01A2 (2011): $112331
FUNCTIONAL ANALYSIS OF ERM PROTEINS IN EPITHELIAL MORPHOGENESIS
I Andrea, Professor And Chairman
University Of Chicagocity: Chicago country: United States (us)
Grant 5R01GM087558-02 from National Institute Of General Medical Sciences
Abstract: The ability to form specialized membrane domains composed of unique sets of transmembrane proteins, associated cytoplasmic proteins, and phospholipids, is a fundamental property of polarized epithelial cells. Membrane domains, such as the apical surface or junctional complex, allow spatial segregation of functions at the plasma membrane that are essential for polarized epithelia. Central to this process is the formation of protein complexes on the cytoplasmic side of the membrane that localize transmembrane proteins, regulate their signaling output and control their abundance via regulated endocytosis. The Ezrin, Radixin, Moesin (ERM) proteins organize a key role in this process. In this proposal we describe experiments designed to take advantage of the combined expertise of two investigators, Andrea McClatchey (Harvard/MGH) and Richard Fehon (University of Chicago), to extend our understanding of ERM function. The investigators and their laboratories bring together expertise in two powerful experimental systems, the mouse and Drosophila. The proposed research utilizes a multifaceted approach, including genetics, biochemistry, cell biology and proteomics to better understand the functions of these highly conserved proteins. Specifically, we plan to 1) Determine the molecular mechanisms that link the ERM proteins to the activation state of Rho in developing epithelial cells. 2) Examine the molecular mechanisms that regulate ERM activity, particularly in the context of how ERM activity is dynamically regulated. 3) Delineate the function of the ERM proteins in cellcell junction remodeling. 4) To build an integrated model of ERM-mediated complex formation. These experiments are expected to provide novel insight into the functions of ERM proteins in biological processes such as apical-basal polarity cytoskeletal regulation, intestinal lumen formation and homeostasis, and metastasis. They should also yield a better understanding of the cellular processes that establish specialized membrane domains in polarized cells, and inform our understanding of cytoskeletal and junctional dynamics during morphogenesis and in disease. We will carry out complementary and synergistic studies in two powerful model systems - Drosophila and the mouse - to examine the function of ERM proteins in epithelial morphogenesis. Specifically, we will test the hypothesis that ERM proteins provide local regulation of RhoGTPase activity in response to upstream signals/receptors using molecular tools and genetic models that we have developed in each system. We will also delineate the function of ERM proteins in cell junction remodeling/stability as suggested by the phenotypes of ERM loss in both flies and mammals
Keywords: Actins; Adherens Junction; Adhering Junction; Adhesions; Adhesive Junction; Anchoring Junction; Apical; Autoregulation; Biochemistry; Biological; Biological Function; Biological Models; Biological Process; biological signal transduction; Body Tissues; bowel; cancer metastasis; cell biology; Cell Communication and Signaling; Cell Function; Cell Junctions; Cell membrane; Cell physiology; Cell Process; Cell Shape; Cell Signaling; Cell to Cell Communication and Signaling; Cell-Cell Signaling; Cells; Cellular biology; Cellular Function; Cellular Matrix; Cellular Physiology; Cellular Process; Chemistry, Biological; Chicago; Complex; Cytoplasmic Membrane; Cytoplasmic Protein; Cytoskeletal System; Cytoskeleton; design; designing; Disease; disease/disorder; Disorder; Drosophila; Drosophila genus; EC 2.7; Endocytosis; Epithelial; Epithelial Cells; Epithelium; Epithelium, Intestinal; experiment; experimental research; experimental study; ezrin; Family; Flies; fly; fruit fly; Fruit Fly, Drosophila; gene product; Genetic; Genetic Models; Goals; Homeostasis; in vivo; insight; Integral Membrane Protein; intercellular communication; Intercellular Junctions; Intestinal; intestinal epithelium; Intestines; Intracellular Communication and Signaling; intracellular skeleton; Intrinsic Membrane Protein; Investigators; Kinases; Laboratories; Link; Mammalia; Mammalian Cell; Mammals; Mammals, General; Mammals, Mice; Mediating; Membrane; membrane structure; membrane-organizing extension spike protein; Metastasis; Metastasize; Metastatic Neoplasm; Metastatic Tumor; Mice; Model System; Modeling; Models, Biologic; moesin; Molecular; Morphogenesis; Murine; Mus; mutant; Na+-H+ exchanger-regulatory factor; Neoplasm Metastasis; NHE-RF protein; NHERF; novel; Output; Phenotype; Phosphatides; Phospholipids; phosphoprotein p81; Phosphorylation; Phosphotransferases; Physiological Homeostasis; Plasma Membrane; plasmalemma; Play; polarized cell; Post-Translational Modifications; Post-Translational Protein Processing; Posttranslational Modifications; Process; Property; Property, LOINC Axis 2; protein complex; Protein Modification; Protein Modification, Post-Translational; Protein Phosphorylation; Protein Processing, Post-Translational; Protein Processing, Posttranslational; Protein/Amino Acid Biochemistry, Post-Translational Modification; Proteins; Proteomics; public health relevance; Racial Segregation; radixin; radixin protein; Receptor Signaling; Regulation; Research; Research Personnel; research study; Researchers; response; rho; Role; Secondary Neoplasm; Secondary Tumor; segregation; Side; Signal Transduction; Signal Transduction Systems; Signaling; social role; sodium-hydrogen exchanger regulatory factor; sterile; Sterility; Structure of intestinal epithelium; Subcellular Process; Surface; System; System, LOINC Axis 4; Testing; Tissues; tool; Transmembrane Protein; Transphosphorylases; Tumor Cell Migration; Universities; Work
Relevance: We will carry out complementary and synergistic studies in two powerful model systems - Drosophila and the mouse - to examine the function of ERM proteins in epithelial morphogenesis. Specifically, we will test the hypothesis that ERM proteins provide local regulation of RhoGTPase activity in response to upstream signals/receptors using molecular tools and genetic models that we have developed in each system. We will also delineate the function of ERM proteins in cell junction remodeling/stability as suggested by the phenotypes of ERM loss in both flies and mammals
Project start date: 2010-01-01
Project end date: 2013-12-31
Budget start date: 1-JAN-2011
Budget end date: 31-DEC-2011
PFA/PA: PA-07-070
5R01GM087558-02 (2011): $454751
5R01GM087558-03 (2012): $445486